1. Field of the Invention
The present invention relates generally to an oil separator for blow-by gases that need to be vented from a crankcase of an internal combustion engine and more particularly, to a new and improved oil separator for oil laden blow-by gases that utilizes a nozzle having a plurality of holes to direct the flow of such gases against an impingement plate or wall so as to extract oil from the crankcase blow-by gases.
2. Background of the Invention
In an internal combustion engine, the crankcase needs to be vented due to the flow of gases from the combustion chambers past the piston rings into the crankcase. The gases flowing from the combustion chambers are typically referred to as blow-by gases. The high gas velocities resulting from the movement of the pistons cause oil droplets to be carried with the blow-by gases into the crankcase and as a result into the crankcase ventilation system. In the case of passenger automobiles, these blow-by gases are recirculated through a PCV (Positive Crankcase Ventilation) system back into the combustion chambers via the air intake system of the engine. This type of recirculation of the blow-by gases is sometimes referred to as a closed system. The oil droplets in the blow-by gases are in a mist state and will tend to cause problems within the engine control mechanisms if recycled back into the engine. On the other hand, diesel engines used in trucks have open crankcase ventilation systems wherein the crankcase is ventilated to the atmosphere. This is sometimes accomplished by a road draft tube that extends downwardly from the truck engine so that the blow-by gases from the crankcase laden with oil are expelled onto the roadway.
The open diesel truck ventilation system has the advantage that the oil laden blow-by gases are not recirculated back into the engine where they can cause problems to the proper operation of the engine. However, the oil laden air in such an open system is spilled onto roadways which is not environmentally desirable and may be contrary to future EPA standards. In order to separate the oil from the blow-by gases prior to being expelled from the road draft tubes, a variety of oil separators have been used. One such oil separator used in diesel engines for trucks is commonly known as a gimp. A gimp includes a stainless steel wire filter that is placed in the air flow path of the blow-by gases in the crankcase. The oil particles in the blow-by gases coalesce onto the steel wire and drips back into the engine oil reservoir such that the blow-by gases that are ventilated from the crankcase have a decreased oil content. Such gimps do not produce the desired amount of oil separation from the blow-by gases and can become clogged so as to inhibit the venting of the crankcase by inhibiting the flow of the blow-by gases. Moreover, the crankcase pressures found in diesel truck engines can be so significant that as the oil collects on the steel wires of the gimps the oil will be literally blown through the gimp and reintroduced into the blow-by gases that are being vented through the road draft tube onto the roadway.
U.S. Pat. No. 4,627,406 discloses another form of an oil separator for recycled blow-by gas. The disclosed separator utilizes a pair of perforated plates with filter plates located downstream of each of the plates. Each of the plates has a set of perforations, but the sets are not in alignment and thus do not present the type of air flow path that is desirable for blow-by gases being expelled from high compression diesel engines. Moreover, the filter plates are in the path of the blow-by gases and thus present the same problems associated with gimps when they are disposed in the air flow path of the blow-by gases.